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A dual-polarised dielectric-loaded monopole antenna for wideband communication applications is presented. The antenna is constructed by using two antenna elements orthogonal to each other. The antenna element consists of a microstrip-line-fed printed monopole with a finite truncated ground loaded with a dielectric resonator (DR). First, the antenna element is designed, fabricated and experimentally tested. Then the proposed design was extended to develop a dual-polarised antenna. The antenna impedance match is better than 10 dB over 91.3% from 4.4 to 11.8 GHz for both polarisations and the measured isolation between the two polarisation ports is better than 20 dB within the frequency band of interest whereas the maximum isolation achieved is ∼27 dB. The cross-polarisation levels in both planes are better than 20 dB. Both theoretical and experimental results in terms of return loss, isolation and radiation pattern are presented and discussed. [ABSTRACT FROM AUTHOR]

In this study two measurement campaigns are presented, where two types of multiple input multiple output (MIMO) antennas are investigated in an underground mine environment, aiming to identify the optimal antenna technology that allows to improve the performance of MIMO system in terms of root mean square (RMS) delay spread, path loss and capacity. It is found that in such scatter-rich environment, for line of sight scenario the directional antennas have provided significant suppression of multipath, giving a reduction in received RMS delay spread, and a corresponding increase in the correlation, which consequently decrease the channel capacity. [ABSTRACT FROM AUTHOR]

A novel dielectric resonator antenna (DRA) is proposed for ultrawideband (UWB) applications, where a simple rectangular dielectric resonator is excited by a bevel-shaped patch connected to a coplanar waveguide (CPW) feeding line. It is found that the bandwidth of the resonant modes can be expanded by using a CPW-fed ground and bevel-shaped patch, and thus a UWB performance can be achieved. Experimental and numerical results were carried out, showing a good agreement. The measured results demonstrate that the proposed DRA achieves an impedance bandwidth more than 3:1, covering the frequency range from 3.1 to 10.6 GHz, which is suitable for UWB applications. Furthermore, to minimise the potential interferences between the UWB system and narrowband systems, such as world interpretability for microwave access and WLAN, UWB DRAs with single band-notched and dual band-notched characteristics were designed, fabricated and measured. The measurement results show good performances in terms of VSWR, antenna gain and radiation pattern. With these features, the proposed antennas are expected to be good candidates in various UWB systems. [ABSTRACT FROM AUTHOR]

A simple and accurate method for the S-parameter analysis of square periodic H-guide structures is presented and compared to numerically simulated and measured results. For these structures, the H-guide's rectangular dielectric column is supported by thin, periodic dielectric vanes, forming rectangular air holes. Such a structure is closely related to, but performs over a much wider bandwidth than electromagnetic band gap bordered non-radiative dielectric waveguides that operate in a small band gap region. A power-corrected multiple reflection model capable of accurately predicting the square-periodic H-guide's frequency response up to its first resonant frequency using a simple analytical closed form model for vanes of finite thickness is discussed here. [ABSTRACT FROM AUTHOR]

The design and realisation of a 4×4 Butler matrix for multibeam antenna arrays operating at 5.8 GHz are described. The matrix is implemented on a single layer slotline structure to avoid using air bridges as required in coplanar waveguide technology. In this design, a new hybrid coupler and a crossover using slotline technology were designed and fabricated, and they are used to build a new Butler matrix. To examine the performances of the proposed matrix, numerical simulations and experimental measurements were carried out; the comparison between simulated and experimental results shows a good agreement. [ABSTRACT FROM AUTHOR]

A new wideband 3 dB directional coupler based on CB-CPW technology is presented and implemented. The proposed coupler is elliptic, offering a wide bandwidth compared to the conventional branched-arm hybrid technology. In fact, simulated and measured results show a better performance, especially in terms of bandwidth (∼50%) compared to conventional CPW branch-line hybrid couplers. This novel architecture is useful for low-cost wideband applications. [ABSTRACT FROM AUTHOR]

A new ultra-wideband bandpass filter using a back-to-back CBCPW-to-CBCPW transition structure is presented. The filter is composed of two CBCPW-to-CBCPW transitions and a section of a CBCPW line section used as a multiple-mode resonator. Using this transition, a new ultra-wideband filter prototype was designed, fabricated and measured. Obtained results show that the proposed filter can easily cover the band from 3.1 to 10.6 GHz. [ABSTRACT FROM AUTHOR]

The main objective of this study was to demonstrate that the human body may be approximated by a uniform geometrical shape. A perfect conducting circular cylinder of radius of 0.25 in was reasonably considered to be the closest form of substitute for the human body in human effect investigations. To validate the model, continuous- wave measurements were performed at 10 GHz between two fixed terminals in an empty room along with the presence of an obstacle (human body or cylinder) moving in predetermined parallel and perpendicularly crossing paths with respect to the direct line of sight. Results indicate that there is a strong correlation between the human body and a perfect conducting cylinder. The results obtained will be of great interest for ray-tracing techniques that involve a human motion within indoor propagation channel. [ABSTRACT FROM AUTHOR]

A novel design for single layer slot antennas is presented. The antenna consists of a rectangular slot on the top of a substrate and two parasitic patches with a coplanar feed-line on the opposite side. The simulated and experimental data show good performances in terms of bandwidth and unidirectional radiation. [ABSTRACT FROM AUTHOR]

A novel compact ultra-wideband (UWB) printed monopole loaded with a dielectric resonator (DR) antenna is proposed. The antenna consists of a microstrip fed monopole printed on a substrate with a truncated ground plane loaded with a DR. The bandwidth is enhanced by making an inner groove inside the DR and controlling the slot width of the truncated ground. [ABSTRACT FROM AUTHOR]

A new ultra-wideband back-to-back conductor-backed coplanar waveguide (CBCPW)-to-CBCPW transition structure is presented and implemented. The design of this transition is based on vertical resonant coupling via a rectangular slot between two stacked CBCPW lines. According to careful design and optimisation, the CBCPW-to-CBCPW transition results show a good performance in terms of bandwidth, which is about 12 GHz. [ABSTRACT FROM AUTHOR]

A correction to the article "Ultra-wideband CPW sixport circuits based on multilayer technology" that was published in the 2007 issue is presented.